The invention pertains to methods of forming encapsulant over semiconductor dies, such as, for example, methods of forming die packages.
A prior art method of forming a die package is described with reference to FIGS. 1-7. Referring first to FIG. 1, such illustrates a fragment of an assembly 10 comprising an insulative material substrate 12. Insulative substrate 12 comprises a top surface 13 and slits 18 extending therethrough. Circuitry 16 is formed on top surface 13. Circuitry 16 and slits 18 form repeating patterns across top surface 13. The repeating patterns define separate units 19, 21 and 23, each of which ultimately forms a separate die package.
Referring to FIGS. 2-4, an enlarged segment of substrate 12, corresponding to unit 21, is shown in three different views. FIG. 2 is a top view similar to the view of FIG. 1, FIG. 3 is an end view, and FIG. 4 is a cross-sectional top view along the line 4xe2x80x944 of FIG. 3.
Substrate 12 comprises a bottom surface 15. A semiconductive-material-comprising die (or chip) 14 is adhered to bottom surface 15 via a pair of adhesive strips 20. Strips 20 can comprise, for example, tape having a pair of opposing surfaces 22 and 24, with adhesive being provided on both of such opposing surfaces. Adhesive strips 20 space die 14 from insulative substrate 12, and accordingly form a gap 26 between die 14 and insulative material 12. Strips 20 can accordingly be considered spacers. Gap 26 is in the form of a channel that extends from one end of strips 20 to another end of strips 20. Preferably, strips 20 comprise insulative material such that strips 20 do not form an electrical connection between die 14 and conductive circuitry associated with substrate 12.
Wire bonds 28 (only some of which are labeled in FIG. 2) extend from circuitry 16, through slit 18 and gap 26, to electrically connect circuitry 16 to bonding pads 25 (only some of which are labeled in FIG. 2) associated with die 14, and to accordingly electrically connect circuitry 16 with circuitry (not shown) comprised by die 14. (The wire bonds and bonding pads are not shown in FIGS. 3 and 4 for purposes of clarity in the illustrations.)
After wire bonds 28 are formed, an encapsulant is provided over wire bonds 28 to protect such wire bonds. A method of providing the encapsulant is described with reference to FIGS. 5 and 6. Referring to FIG. 5, the die assembly of FIG. 4 is shown at an initial stage of the encapsulant-forming methodology. Specifically, dams 27 and 29 are formed at ends of gap 26. Such dams can be formed by, for example, dispensing and curing liquid encapsulant at the die sides.
Referring to FIG. 6, an encapsulant 30 is provided through slit 18 after dams 27 and 29 (FIG. 5) are formed. Specifically, an injector 31 is provided over slit 18 and utilized to inject encapsulant 30 through slit 18 and into gap 26 to substantially fill gap 26 and slit 18. By xe2x80x9csubstantially fillxe2x80x9d it is meant that the encapsulant fills more than half of the combined space of gap 26 and slit 18. In particular applications, the encapsulant can completely fill gap 26 and slit 18. The encapsulant utilized is generally a heat curable epoxy. Accordingly, the encapsulant is provided within gap 26 as a liquid, and subsequently subjected to heat to cure the encapsulant into a more solid form.
After encapsulant 30 is provided and cured, circuitry 16 and die 14 can be subjected to additional package-forming steps. For instance, FIG. 7 illustrates a portion of substrate 12 (specifically, a portion comprising units 19 and 21) at a step subsequent to curing of encapsulant 30. Conductive balls 31 (only some of which are labeled) have been formed over portions of circuitry 16 to form a ball grid array which can be subsequently utilized to form a plurality of interconnects from circuitry 16 to other circuitry (not shown).
FIG. 7 further illustrates that substrate 12 can be subjected to a singulation process to separate units 19 and 21 from one another, and thus form individual die packages from units 19 and 21.
It would be desirable to develop alternative methods of forming semiconductive die packages. It would be particularly desirable to develop alternative methods of providing encapsulant over wire bonds associated with semiconductive die packages.
In one aspect, the invention encompasses a semiconductor processing method. An insulative substrate is provided. Such substrate has a pair of opposing surfaces and an opening extending therethrough. The opening extends from one of the opposing surfaces to another of the opposing surfaces. A semiconductor-material-comprising die is provided adjacent to said one of the opposing surfaces of the insulative substrate, and the die has an edge. A gap is between the die and insulative substrate, and exposed through the opening. A liquid radiation-curable material is flowed through the opening and into the gap. Radiation is directed from beside the die to cure at least a portion of the radiation-curable material within the gap and thus form a dam which impedes non-cured radiation-curable material from flowing beyond the edge.
In another aspect, the invention encompasses a method of forming a die package. An insulative substrate is provided, and such substrate has an underside and an opposing topside. Circuitry is over the topside of the insulative substrate, and a slit extends through the insulative substrate. A semiconductive-material-comprising die is provided beneath the underside of the insulative substrate, and has a surface exposed through the slit in the insulative substrate. The die has an edge. There is a gap between the die and the underside of the insulative substrate. A radiation-curable material is injected through this slit and into the gap. Radiation is directed from over the edge to the gap to cure at least a portion of the radiation-curable material within the gap and thus form a dam which impedes non-cured radiation-curable material from flowing beyond the edge.